The Vortex EBR-1 MOA reticle is designed for long distance shooting and ranging abilities in their 2.5-10x44 riflescope. It can be used to determine ranges, holdovers, windage corrections, and moving target leads. The fine center crosshair subtensions were carefully chosen to provide precision aiming and low light visibility. The reticle is based on MOA measurements which correlate to specific inch measurements at distances and can be used for ranging targets and correcting for bullet drop, wind, and moving targets. Vortex provides an unconditional lifetime warranty on their riflescopes.

1. 2.5-10x44 ebr-1 RETICLE (moa)
Second Focal Plane | Uncapped Turrets
RIFLESCOPE

2. The Vortex® EBR-1 MOA Reticle
3
RIFLESCOPE
Designed to maximize long distance shooting and ranging abilities, the
EBR-1 MOA reticle for the Viper®PSTTM
2.5–10x44 riflescope can be
used to effectively determine ranges, holdovers, windage corrections
and moving target leads. Ultra precision laser etching on the glass
reticle ensures that minute of angle (MOA) specifications can be kept
to the tightest tolerances possible. The fine center crosshair subtensions
on the EBR-1 MOA reticle were carefully chosen to provide the
optimum balance between precision aiming and low light visibility.
Note: Reticle images shown in this manual are for representation
only—images vary between scope models depending on magnification
and reticle plane.
Dual Use: Shooting Tactical / Hunting
US Patent 7,937,879

3. 54
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MOA Subtensions
The EBR-1 reticle is based on minute-of-angle (MOA) subtensions.
MOA measurements are based on degrees
and minutes: 360 degrees in a circle, 60
minutes in a degree for a total of 21,600
minutes. These angular measurements
are used to estimate range and correct for
bullet trajectory drop in riflescopes. 1 MOA
will correspond to 1.05 inches at a 100
yard distance, 2.1 inches at 200 yards, 3.15
inches at 300 yards, and so on.
EBR-1 MOA Reticle Subtensions
In the Viper PST second focal plane
riflescopes, the listed MOA subtensions
of the EBR-1 reticle are only valid at
the highest magnifications of the scope.
However, by understanding the relationship
of magnification and subtensions,
ranging, holdovers, and wind drift can still be calculated at partial
magnifications. Here are some examples:
• If the magnification is set at 1/2 the full magnification, subtension
values will be two times the spec listed in the manual.
• If the magnification is set at 1/3 the full magnification, subtension
values will be three times the spec listed in the manual.
• If the magnification is set at 1/4 the full magnification, subtension
values will be four times the spec listed in the manual.
Although 1 MOA is very
commonly corresponded to
1 inch at 100 yards, this is
not quite correct. 1 MOA
at 100 yards equals 1.05
inches. Calling 1 MOA
an inch per 100 yards may
be acceptable at shorter
distances, but it will cause a
five percent error in ranging
and holdover adjustments.
This will result in missed
shots at longer distances.
Estimating MOA
Heavy crosshair
subtends 2.5 MOA
Fine crosshair
subtends .15 MOA
Gap subtends
2. 5 MOA
5 MOA 2 MOA
2.5–10x44 Reticle Subtensions
(Valid at 10x)
RIFLESCOPE
MAGNIFICATION
10x
5x
3.3x
2.5x
2 MOA
4 MOA
6 MOA
8 MOA
ACTUAL SUBTENSION OF
2 MOA RETICLE SPACE
Subtension Changes with Magnification

4. 76
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MOA measurements are very effective for ranging using a simple formula.
To use this formula, the shooter needs to know the size of the target or
nearby object in inches.
Using either the vertical or horizontal MOA scale, place the reticle on
a target of known dimensions and read the number of MOAs spanned.
You will obtain maximum accuracy in ranging by calculating exact
MOA measurements. MOAs should be estimated in 1/4s if possible.
Ranging
Accurate measuring will depend on a very steady hold. The rifle
should be solidly braced using a rest, bipod or sling when measuring.
Once you have an accurate MOA reading, use the formula to
calculate the distance.
Note: In the MOA ranging formula, a shooter may substitute 100 for
95.5 in the interest of speedier calculations. Be aware that this will
produce a five percent over-estimation error of the yardage distance
obtained.
Ranging a 6-foot target (72 inches) at 10 MOAs yields 688 yards.
72 x 95.5
10 MOA
688 Yards=
Target Size (Inches) x 95.5
Measured MOAs
Range (Yards)=
MOA Ranging Formula
Example

5. 98
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Elevation Holdovers
Once the distance has been calculated using the EBR-1 MOA
reticle, or a laser rangefinder, the EBR-1 can be used for rapid
holdover correction for bullet drop of the cartridge being used.
To get the most benefit out of the EBR-1 equipped riflescope,
Vortex Optics highly recommends shooters learn their bullet drop
numbers in MOAs rather than inches.
Since the EBR-1 reticle is scaled in 2 MOA increments, it is an
easy job to quickly select the correct drop reference line once the
shooter knows the bullet drops in MOAs. If the shooter prefers to
dial come ups for bullet drop using the elevation knob, knowing
bullet drops in MOAs rather than inches will allow for much faster
adjustments as the MOAs can be quickly read on the elevation
knob.
17.5 MOA reticle holdover at 625 yards. No wind.
Example

6. 1110
RIFLESCOPE
Windage and Moving Targets
The EBR-1 MOA reticle is highly effective when used for wind
and moving target leads. Using the reticle for effective windage
and moving target leads will require thorough knowledge of
your weapons system’s ballistic performance under varying
conditions and experience in reading wind strengths and target
speeds. As in bullet drops, it is important for the shooter to
learn a particular weapon’s windage/moving target corrections
in MOAs rather than inches. Always hold the reticle into the
wind.
3 MOA reticle windage correction at 400 yards in 10 mph crosswind using
center crosshair. Elevation adjustment already dialed into the riflescope.
When dialing elevation come ups, the center horizontal crosshair
will be used for windage or moving lead corrections.
Basic windage correction on center crosshair
10 mph wind
Full value wind at 90 degrees
Example

7. 1312
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When using the reticle for elevation correction rather than dialing, the
MOA marks on the center horizontal crosshair can still be used to help
visually reference windage corrections. Remember to hold the reticle
into the wind.
Basic windage correction using drop line on reticle
When estimating moving target leads, the MOA marks on the center
horizontal crosshair can be used. Estimating moving target leads will require
knowing yardage distance, wind speed, moving target speed, and total bullet
flight time (including rifle lock time). Bullet flight times can be roughly
calculated based on fps velocities or a ballistic calculator.
Basic moving lead correction
9.4 MOA reticle correction for a target moving 3 mph at a distance of 800 yards.
No wind. Total bullet time of flight from trigger pull is 1.5 seconds during which
target travels 6.6 feet. Elevation already dialed into turret.
20 mph wind
Full value wind at 90 degrees
8 MOA reticle windage correction at 500 yards in 20 mph crosswind using
12 MOA reticle drop line.
Note: Correctly estimating moving leads is very difficult and requires
considerable practice and knowledge beyond the scope of this manual.Example
Direction of Movement
Example

8. 1514
RIFLESCOPE
THE VIP WARRANTY
We build optics based on our commitment to your absolute satisfaction.
That’s why Vortex products are unconditionally guaranteed and we
make this Very Important Promise to you—a Very Important Person.
Rest assured that in the event your Viper PST becomes damaged or
defective, Vortex Optics will repair or replace the
riflescope at no charge to you. Call Vortex Optics
at 800-426-0048 for prompt, professional, and
friendly service.
Vortex Optics
2120 West Greenview Drive
Middleton, WI 53562
service@vortexoptics.com
Visit www.vortexoptics.com for more information. Canadian customers
may visit www.vortexcanada.net for customer service information.
Note: The VIP warranty does not cover theft, loss, or deliberate damage
to the product.
Lifetime Warranty
Unlimited
Unconditional

9. #PST-R43103-12A
® Vortex Optics USA
#PST-R210S1-A-12A
©Vortex Optics USA
WWW.VORTEXOPTICS.COM
RIFLESCOPE